Well, that would be called a Custom Extension. But you need
to use the product attributes, to only display available options, but
without any functions to them. It would be rather complicated, and
so expensive too, to create a Custom Mod, just to achieve such, I assume.
But other Custom Field Cat 'Sections' also exist, you might use one of them.

As Ernie said: possible by a custom extension.
But is not that complicated as he says and also not that exensive.

But what kind of options you want to display?
Always only the size?
And what if you have 20 sizes, display them all - just in a row, seperated by a comma?
And would need also the OpenCart version you are using.